micro-utils/src/sysutils-linux/dmesg/dmesg.c

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2024-07-01 10:23:00 +00:00
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/klog.h>
int main(int argc, char **argv) {
unsigned int s_size = 0;
unsigned int n_level = 0;
int opt;
while ((opt = getopt(argc, argv, "s:n:")) != -1) {
switch (opt) {
case 's':
s_size = atoi(optarg);
break;
case 'n':
n_level = atoi(optarg);
break;
default:
printf("dmesg [sn]\n\t-n LEVEL Set console logging level\n\t-s SIZE Buffer Size\n");
return 0;
}
}
/* Setup */
if (n_level)
if (klogctl(8, NULL, (long)n_level) < 0) {
fprintf(stderr, "dmesg: %s\n", strerror(errno));
return 1;
}
if (!s_size)
s_size = klogctl(10, NULL, 0);
/* Get kernel log */
char *buf = malloc(s_size + 1);
if (buf == NULL) {
fprintf(stderr, "dmesg: malloc failed\n");
return 1;
}
int n = klogctl(3, buf, s_size);
if (n <= 0) {
free(buf);
if (n == 0)
return 0;
fprintf(stderr, "dmesg: %s\n", strerror(errno));
return 1;
}
/* Print */
if (write(STDOUT_FILENO, buf, n) != n)
fprintf(stderr, "dmesg: %s\n", strerror(errno));
putchar('\n');
free(buf);
return 0;
}